IPv4 configuration

Due to obvious reasons, IPv4 is fully supported in default firmware.

The following sections describe the configuration of IPv4 connections to your ISP or an upstream router.

For an uplink with native IPv4 connectivity you can just use the default configuration.

config interface 'wan'
	option device 'eth0.2'
	option proto 'dhcp'

Name	Type	Required	Default	Description
`ipaddr`	ip address	yes, if no `ip6addr` is set.	(none)	IP address. [openwrt 12.09] It could be a list of ipaddr , that is: several ipaddresses will be assigned to the interface. If, instead of a list, several ipaddr are specified as options, only the last is applied.
`netmask`	netmask	yes, if no `ip6addr` is set	(none)	Netmask
`gateway`	ip address	no	(none)	Default gateway
`broadcast`	ip address	no	(none)	Broadcast address (autogenerated if not set)
`dns`	list of ip addresses	no	(none)	DNS server(s)
`dns_metric`	integer	no	`0`	DNS metric
`dns_search`	list of domain names	no	(none)	Search list for host-name lookup, relevant only for the router
`metric`	integer	no	`0`	Specifies the default route metric to use

Name	Type	Required	Default	Description
`broadcast`	boolean	no	`0`	Enable the broadcast flag in DHCP requests, required for certain ISPs, e.g. Charter with DOCSIS 3
`ipaddr`	IP address	no	(none)	IP address to request from the DHCP server
`hostname`	string	no	system hostname	Hostname to include in DHCP requests (option 12)
`clientid`	string	no	(none)	Override client identifier in DHCP requests (option 61)
`vendorid`	string	no	`udhcp VERSION`	Override the vendor class in DHCP requests (option 60)
`dns`	list of ip addresses	no	(none)	Supplement DHCP-assigned DNS server(s), or use only these if peerdns is 0
`peerdns`	boolean	no	`1`	Use DHCP-provided DNS server(s)
`defaultroute`	boolean	no	`1`	Whether to create a default route via the received gateway
`customroutes`	string	no	(none)	Space-separated list of additional routes to insert via the received gateway
`metric`	integer	no	`0`	Specifies the route metric to use for both default route and custom routes
`classlessroute`	boolean	no	`1`	Whether to request the “classless route” option (DHCP option 121) — available since LEDE r2001
`reqopts`	string	no	(none)	Space-separated list of additional DHCP options to request from the server
`sendopts`	string	no	(none)	Space-separated list of additional DHCP options to send to the server. Syntax: `option:value` where `option` is either an integer code or a symbolic name such as `hostname`.
`norelease`	boolean	no	`0`	If set DO NOT release DHCP address on interface shutdown
`zone`	firewall zone	no	(none)	Firewall zone to which this interface should be added

These parameters are handled partially by netifd (in interface.c) and partially by a shell script in lib/netifd/proto/dhcp.sh. Note prior to commit 3cee6f3f24 the norelease option was known as release and had the opposite sense.

Outdated information, please proofread and test it:

If an interface is configured as DHCP client, the default route received by DHCP will be the only one listed and will remove other default route/metrics defined for other interfaces if those interfaces comes “before” the interface with DHCP in terms of “device” values. For example:

config interface 'wan'
    option device 'eth0'
    option proto 'static'
 
config interface 'wan2'
    option device 'eth1'
    option proto 'dhcp'

The interface with DHCP comes after (because eth1 comes after eth0 in a lexicografical order) and will overwrite the default routes set up by the interface “wan”, while the contrary is not true:

config interface 'wan'
    option device 'eth0'
    option proto 'dhcp'
 
config interface 'wan2'
    option device 'eth1'
    option proto 'static'

Both default routes set up by wan and wan2 will appear in the routing table.

For a downlink with IPv4 connectivity you can just use the default configuration, DHCP server is enabled by default, please see DHCP configuration for more details on that.

config interface 'lan'
	option device 'br-lan'
	option proto 'static'
	option netmask '255.255.255.0'
	option ip6assign '60'
	option ipaddr '192.168.1.1'
 
config device 'lan_dev'
	option name 'br-lan'
	option type 'bridge'
	list ports 'lan3'
	list ports 'lan4'

IPv4 configuration

Upstream configuration for WAN interfaces

Protocol "static", IPv4

Protocol "dhcp"

Downstream configuration for LAN interfaces